Well, I hate to say it, but the diagnosis: turns out you're human.
Most of us lose it now-and-then and just romp on it (especially with a lot of us with backgrounds in racing, or just liking to drive fast).
It's cool that you can admit to it -- I know on long trips (especially with Rental cars), I don't hypermile like I should (especially on long days).
...just rented a Corolla LE auto. (Atlanta-Augusta-Atlanta) Even with speeds of 70+ and city driving, the average FE was 36.x MPG. I have to hypermile the 'Teg like mad to get that.
The best thing to do, is get back on it tomorrow. It takes a lot of patience to hypermile, so don't expect it overnight. In time you'll get it...
RH77